IA idea · Modelling with functions
Is Moore's law still true?
Research question
Has the number of transistors on microprocessors doubled every two years since 1971, and is there evidence that the doubling time has changed?
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Why it makes a good exploration
Moore's law is quoted everywhere, usually without checking. Fitting an exponential model, extracting the doubling time and testing whether it has changed over different decades is a precise, answerable question.
The mathematics you'll need
- Exponential models and doubling time
- Logarithms to linearise data
- Linear regression on log-transformed data
- Comparing gradients across time periods
Modelling the data, step by step
This idea usually needs exponential or straight-line models. See it worked step by step, with a criterion tip at every step: Exponential y = a e^(kx) + c and y = a·bˣ · Straight line y = mx + c.
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Where the data comes from
Download the “transistors per microprocessor” dataset from Our World in Data.
Real data for this idea
- Primary source: Karl Rupp, microprocessor trend data: Microprocessor trend data. The transistors file gives year and transistor count per chip: fit log(count) against year. Licence: Check the repository's licence file.
- Readable chart: Our World in Data: Moore's law: The number of transistors per microprocessor. Use it to see the pattern; download your numbers from the primary source or the chart's own download. Cite as: Our World in Data, ‘Moore's law: The number of transistors per microprocessor’, CC BY 4.0. Original source: Rupp (2022).
Links checked October 2026; we link to the data and never copy it. More free data sets.
A possible outline
- State Moore's claim precisely (doubling every two years).
- Plot log₂ of transistor count against year.
- Fit a line and convert the gradient to a doubling time.
- Fit separate lines to each decade and compare doubling times.
- Discuss what the log scale hides and what limits further growth.
Pitfalls that cost marks
- Fitting y = abˣ without explaining the log transformation.
- Treating the dataset as one chip per year (it is a scatter of chips).
- Not checking residuals on the log scale.
Showing personal engagement
- Predict the transistor count of the processor in your own phone or laptop and look it up.
- Discuss whether a slowdown is visible and propose a model that captures it.
- Compare with another exponential claim in technology.
See Criterion C: personal engagement for what examiners look for.
Which course is it for?
| Course | Fit | Maths to lean on |
|---|---|---|
| AA SL | Good fit | Exponential models and doubling time; Logarithms to linearise data |
| AA HL | Fits, but add an HL technique | Exponential models and doubling time; Logarithms to linearise data |
| AI SL | Good fit | Exponential models and doubling time; Logarithms to linearise data |
| AI HL | Fits, but add an HL technique | Exponential models and doubling time; Logarithms to linearise data |
Level: Accessible. A good first extended piece of maths, with room to go deeper. See how the IA differs between AA and AI, SL and HL.
How this idea reaches the top bands
Reflection (D)
For this idea, start with the weak points: fitting y = abˣ without explaining the log transformation; and treating the dataset as one chip per year (it is a scatter of chips). Say how each one affects your answer.
Use of mathematics (E)
SL: exponential models and doubling time; logarithms to linearise data; linear regression on log-transformed data; comparing gradients across time periods, each explained in your own words and carried out correctly.
How modelling explorations reach the top bands in general: Modelling with functions IA ideas. Guides: A · B · C · D · E · self-grade sheet.
Taking it further
Test whether a logistic or piecewise model fits significantly better, or compare with the growth of hard-drive capacity.
Extending it for HL
Add an HL technique the question genuinely needs: what an HL modelling exploration adds.
See a complete IA, marked
Should I lease or buy my first car? (AI SL) is a complete modelling exploration, marked on every criterion.
Frequently asked questions
Which IB Maths course is this IA idea for?
It works for AA SL, AI SL, AA HL and AI HL. We rate it Accessible: a good first extended piece of maths, with room to go deeper.
What mathematics does this IA use?
Exponential models and doubling time, logarithms to linearise data, linear regression on log-transformed data and comparing gradients across time periods.
Where can I get data for this IA?
Download the “transistors per microprocessor” dataset from Our World in Data. Checked sources and tools: Karl Rupp, microprocessor trend data and Our World in Data.
Turn this idea into your IA
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